Hay conditioners generally include a pair of rollers mounted in co-extensive parallel relationship for rotation about respective axes with the crop arranged to pass between the rollers in a conditioning action.
Each of the rollers carries a plurality of longitudinally extending angularly spaced flutes which project outwardly from the surface of the roller. The rollers are Spaced by a distance such that the flutes intermesh generally without contact between the rollers. The intermeshing of the flutes causes the crop material to be bent as it passes between the rollers causing a cracking of the waxy surface of the crop stem.
It is necessary in such rollers to allow one of the rollers, generally the top roller, to move in a direction to increase the spacing between the axes of the rollers to accommodate different amounts of crop material passing between the rollers and to accommodate obstacles such as stones and sticks which pass through without damage to the rollers. Generally this movement is provided by suspending each end of the top roller on a spring biasing system which allows each end independently to rise and lower in a floating action.
In view of the fact that the rollers carry intermeshing flutes, it is essential to ensure that the rollers are driven in synchronism at all times including accommodating the lifting movement while synchronism is maintained.
A number of previous designs have been proposed and manufactured to provide the drive from the first roller to the second roller to maintain the necessary synchronism. One arrangement includes a gear box having an input attached to the bottom roller and an output shaft attached to the top roller. The output shaft includes universal joints which allows the output shaft to accommodate the up and down movement of the top roller shaft. The gear box arrangement is expensive and is of relatively wide width.
An alternative arrangement includes a double chain drive system. In this system, a drive sprocket on the end of the bottom roller and two idler sprockets are located in a common plane at right angle to the axis of the bottom roller at the apexes of a triangle. A chain wrapped around these three sprockets engages a fourth sprocket driven by the chain between the drive sprocket and one of the idler sprockets. A second chain communicates drive from a fifth sprocket coaxial with and co-rotatable with the fourth sprocket to a driven sprocket on the end of the top roller. The top roller is then positioned within the apexes defining the triangle and can pivot relative to the axis of the fourth and fifth sprocket. This arrangement is highly complex-involving a high number of idler sprockets thus increasing cost and increasing chain wear. The double chain arrangement also significantly increases the width of the device since it must accommodate the two chains side by side.